Fig:1
Chinese had gunpowder for something like a thousand years and this is what they looked like by 1300, virtually unchanged.
Cast barrel, fired shot, a hand cannon. That was kind the dead end for China.

What held them back? Couldn't forge weld barrels, length of barrel and lifespan limited, poor gas seal, very little accuracy, a front line weapon. They were effective but the use-case was still formation support.